In general, the DSP Builder license is an "increment" to your existing Quartus Standard license using the "alterad" daemon. You should not have to create a whole new license server / port environment to get it to work. You would copy/paste the 3-4 lines into your license.dat file that Quartus information exists and then reload. Should be tagged with C4D5_512A (see below). Same way that you would add individual pieces of IP. Hope that this helps (or that you already resolved the issue).
FEATURE C4D5_512A alterad